Investment in ATC and ATC Holdco (Details-1) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
Apr. 30, 2024	Mar. 31, 2024	Mar. 31, 2023
Schedule of Equity Method Investments [Line Items]
Equity earnings from investment		$ 2,746	$ 2,611
Dividends from investments		2,106	2,206
Capital contributions to investments		1,381	1,527
MGE Transco [Member] \| ATC [Member]
Schedule of Equity Method Investments [Line Items]
Equity earnings from investment		2,722	2,583
Dividends from investments		2,106	2,206
Capital contributions to investments		$ 715	$ 357
MGE Transco [Member] \| ATC [Member] \| Subsequent Event [Member]
Schedule of Equity Method Investments [Line Items]
Capital contributions to investments	$ 1,100

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